MECHANISM OF THE FORMATION OF SEMINAL FRUCTOSE AND FOETAL FRUCTOSE
MECHANISM OF THE FORMATION OF SEMINAL FRUCTOSE AND FOETAL FRUCTOSE
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DOI：
10.1016/0006-3002(60)90086-x
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发表时间：
1960-01-01
期刊：
影响因子：
--
通讯作者：
HERS, HG
中科院分区：
文献类型：
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作者：
HERS, HG
绵羊精囊切片不可逆地将葡萄糖转化为山梨糖醇，将山梨糖醇转化为果糖。由[I-14 c]葡萄糖形成的果糖仅在位置I被标记。在葡萄糖-6-磷酸、TPN和DPN [三磷酸吡啶核苷酸和二磷酸吡啶核苷酸]的存在下，精囊提取物可催化相同的转化。葡萄糖酮和葡萄糖醛酸内酯抑制葡萄糖通过切片或提取物转化为果糖和山梨糖醇。山梨糖醇转化为果糖被乙二胺四乙酸盐抑制，乙二胺四乙酸盐使酮糖还原酶失活。这些观察结果以及新鲜腺体中山梨醇的存在表明，葡萄糖通过精囊转化为果糖是根据以下反应进行的：[图片]葡萄糖+ TPNH + DPN+ [长划线]>果糖+ TPN+ + DPNH母羊胎盘中存在醛糖还原酶，胎儿肝脏中的酮糖还原酶和胎儿血液中的山梨糖醇的含量表明，胎儿果糖可以通过相同的机制形成，葡萄糖在胎盘中转化为山梨糖醇，山梨糖醇在肝脏中转化为果糖。讨论了葡萄糖转化为果糖的各种机制。
Slices of sheep seminal vesicles irreversibly convert glucose to sorbitol and sorbitol to fructose. The fructose formed from [I-14c]glucose is labelled only in position I. The same conversions are catalyzed by extracts of seminal vesicles in the presence of glucose-6-phosphate, TPN and DPN [triphosphopyridine nucleotide and diphosphopyridine nucleotide.] The conversion of glucose to fructose and sorbitol by slices or extracts is inhibited by glucosone and glucuronolactone. The conversion of sorbitol to fructose is inhibited by ethylenediaminetetra-acetate, which inactivates the ketose reductase. These observations as well as the presence of sorbitol in the fresh gland indicate that the conversion of glucose to fructose by seminal vesicles takes place according to the reactions: [image] Sum: Glucose + TPNH + DPN+ [long dash]> Fructose + TPN+ + DPNH The presence of the aldose reductase in the placenta of the ewe, of the ketose reductase in the liver of the foetus and of sorbitol in the foetal blood indicates that the foetal fructose can be formed by the same mechanism, glucose being converted to sorbitol in the placenta and sorbitol to fructose in the liver. The various mechanisms by which glucose could be converted to fructose are discussed.